Broadly speaking contaminated surfaces includes hard surfaces and soft surfaces such as those found in household environments, in industrial environments, surfaces of food products such as fruits, vegetables and meat, and exterior and interior surfaces of the human body that may become exposed to microbes. It also pertains to exterior and interior and exterior surfaces of equipment that can be contaminated, such as those found in the food industry or the medical equipment found in hospitals and health care facilities, as well as surfaces of implanted devices such as catheters, prosthetic cardiac valves and intrauterine devices.
All such surfaces are at risk of contamination if they are exposed to non-sterile water, air. or soil or other environments where microbes are present.
There is a growing scientific recognition that bacterial organisms which actively populate these common surfaces may form organized communities called biofilms. Bacterial cells forming these biofilm communities assume a biological phenotype that is markedly different than their corresponding planktonic (non-surface attached, or free-swimming) bacterial analogs (W. G. Characklis, “Microbial Biofouling Control” in Biofilms, Characklis and Marshall, eds., Wiley & Sons, 1990, J. W. Costerton, Ann Rev. Microb. 49:7110-7145, 1995). Biofilms are a special form of contamination that have been shown to require as much 1000 time the dose of routine biocides in order to eradicate the microorganism contained within, as compared to planktonic forms.
The significantly decreased susceptibility of biofilm cells to biocides has been documented in numerous studies. See for example: A B. Ronner, et al., J. Food Prot. 56:750-758, 1993; J. W. Costerton, supra, 1995, P. Gilbert and M. R. W. Brown, Microbial Biofilms, Lappin-Scott and Costerton, Eds., University Press, 1995; S. Oie, et al., Microbios. 85:223-230, 1996; J. R. Das, et al., Changes In Biocide Susceptibility of Bacteria Following Attachment to Surfaces, poster presentation, American Society of Microbiology Conference on Microbial Biofilms, Snowbird, Utah, 1997; C. Ntasama-Essomba, et al., Veter. Res. 28:353-363, 1997, J. W. Costerton, Internat. J. Antimicrob. Agents 11:217-221, 1999.
Because of the nature of biofilms, today it is common practice that in order to treat and remove or reduce contamination, a 4-step cleaning process is required. This process involves cleaning the surface with a surfactant containing solution, typically at elevated temperatures with scrubbing action, rinsing of the surface with clean water to remove the cleaning agents and biofilms, followed by treatment of the surface with and antimicrobial for the required time frame, followed by rinsing the surface with clean water to remove the antimicrobial agent and bacteria. This 4-step process is expensive because it requires, labor, energy, water and time which increases the cost of doing business. Further it is known that this 4-step process does not prevent regrowth of the organism as the anti-microbial agent is removed through the process thereby leaving the surface available for re-inoculation, biofilm formation and therefore the ability of microbes to grow and flourish.
Whether the contamination occurs from biofilms or free swimming organisms, there is a need for convenient and less labor intensive methods for decontamination of environmental surfaces.
Most chemical products suitable for use on foodstuff or hard food contact surfaces do not have significant antimicrobial and microbicidal properties. Sanitizing products which exhibit significant antimicrobial and/or microbicidal properties have historically been considered unsafe or suspect as containing ingredients which are not classified by the United States Food and Drug Administration (USFDA) as GRAS (Generally Regarded As Safe) for food contact or as a food additive.
Methods and compositions that are safe for use in the food and healthcare industry, would be particularly useful, especially compositions that would be acceptable in organic food production and processing, which require components that are Generally Recognized as Safe (GRAS) by the United States Food and Drug Administration and/or meet the United States Department of Agriculture's National Organic Program requirements.